1. Field of the Invention
The invention relates to apparatus and a method for operating the apparatus whereby combustible gas useful for cooking, lighting, heating, or other purposes can be formed by decomposition of combustible refuse or vegetable matter. Collecting means is provided for collecting combustible gas produced, including a substantial proportion of methane. Means for injecting water, and means for heating the material undergoing decomposition are provided.
2. Description of the Prior Art
Methods to produce methane from organic waste materials, sewage sludge, woody material, greases, and other wastes are known. For example, Teichmann et al in U.S. Pat. No. 3,671,209, issued June 20, 1972, add a fluid such as water to bits of garbage or solid waste matter to produce a pumpable feed mixture stream, which can be preheated and reacted by partial oxidation with a stream of oxygen-rich gas to produce a stream of synthesis gas, fuel gas, and other materials.
Buswell et al in U.S. Pat. No. 1,990,523, issued Feb. 12, 1935, produce methane by controlled bacterial decomposition of cellulosic material such as cornstalks by controlled and regulated bacterial action.
Switzgable in U.S. Pat. No. 4,053,395, issued Oct. 11, 1977, utilizes a plurality of airtight tanks for processing a slurry of biodegradable waste materials, one of the tanks being provided with a cathode and another with an anode for conducting electrolysis reactions to produce hydrogen, which can further react to produce methane.
Other patents showing production of methane in treatment of sewage sludge or other organic waste materials include the following:
U.S. Pat. No. 1,717,100--J. W. Downes--June 11, 1919 PA1 U.S. Pat. No. 3,368,967--T. O Weaver et al--Feb. 13, 1968 PA1 U.S. Pat. No. 3,687,646--A. Brent et al--Aug. 29, 1972 PA1 U.S. Pat. No. 4,057,401--O. W. Boblitz--Nov. 8, 1977